Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare this as a non-destructive, idempotent read with openWorldHint=false, so the safety profile is covered. The description adds substantive behavior beyond that: default and maximum result count, newest-first ordering, the exact fields returned, a note that price-on-request listings are excluded when price_max is used, and the co-brokered/seller-anonymity disclosure. That last point is non-obvious domain behavior an agent could not infer from structured fields.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Two dense sentences that front-load the purpose before detailing filters and return shape, with essentially no filler. The only waste is the redundant 'US only' constraint repeated at the opening and the close, which slightly dilutes an otherwise tight definition.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

There is no output schema, so the description carries the burden of explaining returns — and it does, listing year, model, serial number, total time, location, price (or price on request), and the listing page, plus ordering and the limit default. For an eight-parameter optional-filter search tool, nothing an agent needs in order to call it correctly is missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so every parameter is already documented with examples and ranges, which sets the baseline at 3. The description restates the filter axes (type, make, model, state, year range, max price) but adds little syntax or meaning beyond the schema, apart from clarifying that price_max drops on-request listings — which the schema also states.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description opens with a specific verb+resource ('Search aircraft for sale') and immediately scopes it to the United States, naming the aircraft categories covered and the exact filter dimensions. It is distinguishable from siblings such as list_aircraft and get_aircraft_listing because it is explicitly a filtered search over for-sale inventory.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Usage context is clear: this is the tool for finding aircraft for sale in the US, with the supported filter axes enumerated. The 'US only' exclusion is stated twice, which is a real constraint on when it applies. What's missing is explicit routing to alternatives (e.g., when to prefer list_aircraft or get_aircraft_listing), so it stops short of a 5.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.